Combining percentage errors or adding?

Hey everyone.

I've a question regarding percentage errors. I'm performing my A2 investigation, and I'm writing the analysis. I've come to the section where we assess the uncertainty within the experiment.

I'm doing a colorimetry practical in one of mine. I use two 5ml graduated pipettes to measure 4ml of copper sulphate and 1ml of distilled water respectively.

So, do I combine the two percentage errors using the method found on that Rod Beavon site?
(the whole ΔX = √{(ΔA)2 + (ΔB)2) or do I, because they are the same percentage error, simply add them together?

Reply 1

latentcorpse

if they are both in percentage form u want to use the square root method

Reply 2

Popa Dom

The way I always do complicated uncertainties is I use the values for the measurements that give me the greatest result (i.e in this case the greatest concentration of copper sulphate), and then those that give me the smallest result, and use that to tell me the uncertainty on etiher side of my measurement (then divide the uncertainty by the reading and times by 100 to get the % uncertainty)

Reply 3

hhhhhhhhhhppppp

percentage errors should be in the evaluation shouldnt they?

Reply 4

latentcorpse

i did mine as a seperate section just after my results but the teacher is gonna decide whether i should leave it there or create an appendix to accomodate them - they are annoyingly lengthy!

Latest

Trending

Articles for you

What A-levels do you need to study maths?

What it’s like studying at an online sixth form

What A-levels do you need to study English?

How to find a degree apprenticeship in law

Try out the app

Continue on web